Choose the Right Rainwater Storage Tank

So you’re ready to begin harvesting  rainwater, but after just a few minutes online , you’ve realized  that size options for rainwater storage containers ranges  from as little as 55 gallons to 3,000 gallons or more. How do you know what size is best for you?

First consider these factors:

-How much rainfall do you get in your area? If you live somewhere with frequent, year round rainfall like Seattle or Portland, you won’t need as much rain storage capacity as someone in Phoenix. Here in the Charlotte area, stored rainwater will be most useful during dry spells during late spring to early fall.

-How large is the catchment surface (i.e roof area). If you have a 5,000 square foot house, there will be thousands of gallons to harvest over the course of a year, and a series of 1000 gallon tanks can hold some of it for drier times.  While an 8’x12’ storage shed or greenhouse can still harvest a useful amount of rainwater, something in the 150 to 250 gallon range would be more appropriate for a structure that size.

-What do you intend to use the rainwater for, and how much do you intend to use? If your intent is to irrigate a landscaped half acre property during a one month summer dry spell, or wash your sizable classic car collection, you’d better plan on having some serious rain storage capacity. If the goal is simply to water growing containers on your condo’s terrace, a smaller rain storage tank will do the job.

- Where will the rainwater storage tank be located, and how much space do you have there? Above ground rain tanks are typically placed within 3’ of a downspout, and can get rather bulky as they increase in capacity. Is there room for the tank, and/or room to move around it? How much site prep will be involved in creating a level placed for a tank or series of tanks to sit? If you plan to put your rain storage tank on a rooftop, can the roof safely support the weight of hundreds or even thousands of pounds of rainwater concentrated in one place?

Or try using the formulas below to calculate how much rain water you’ll need:

roof area   X  annual rainfall = maximum available for capture

Then determine….

Most days without rain  X  average daily water use = storage volume required on day one of a dry spell

If, for example, the longest stretch of days without rain was 30 days, and the average daily usage was 40 gallons, then the  volume on hand on day one of a 30 day dry spell would have to be 1200 gallons

Curious how much rainwater can your home, greenhouse, shed, garage, chicken coop, or other structure harvest ? click here to find out.

A Lesson in Lumber

What do a violin, a floor and a greenhouse have in common? They’re all made of lumber milled from trees, but apart from that, little else.  But just as the uses for these wooden projects vary widely, so do the boards used to make them, which were milled from various parts of a range of tree species, using several different sawing methods.

Heartwood, as the name suggests, is cut from the center of the tree. It’s the most dense and therefore strongest part, and also most resistant to decay.

Sapwood comes from the outer portion of the tree, closest to the bark. Sapwood is younger, less dense and not as durable and resistant to decay than heartwood.

The Annual Growth Rings in a log can also tell a lot about how fast the tree has grown and how durable the boards will be. Widely spaced sapwood rings, for example, indicate a tree that has grown quickly and less durable, while closely spaced growth rings indicate slow growth and a denser, more durable lumber.

Knots develop where branches grow out from the trunk of a tree. As the tree grows, the branch remains attached to the pith in the middle of the tree, and a knot forms where the sapwood grows around the branch. While not a huge factor in simple projects like raised beds, knots should be avoided where the lumber will be used for load bearing structures like a greenhouse or even a chicken coop. Because knots shrink at a different rate than the surrounding wood, they often fall out, leaving a hole and weakening the lumber.

The method that lumber is cut from a log can also have a big impact on it’s durability and performance.

Plainsawn, also called flatsawn or "through-and-through." Is the most efficient way to yield boards from a log. The boards are cut in parallel, one right after another, from top to bottom, right through the pith of the log. Plainsawn is the fastest, easiest and most cost effective way to mill a log, can be used for the widest variety of trees, and is consequently the cut most commonly used in sawmills. By some estimates, over 90% of all logs are cut into boards using the plainsawn method.  

Unlike plainsawn boards, Quartersawn boards are cut at a 90 degree angle from the center of the tree. Quartersawn boards are easy to spot because the growth rings run at a right angle to the face of the board. This is referred in the industry as ‘radial grain’.  Why cut boards using the less efficient, more expensive  quartersawn method?

Quartersawn lumber has a much more uniform grain pattern making it ideal for high visibility projects like cabinets, floors, table legs, etc, and while plainsawn boards  have a tendency to shrink, swell, warp, twist, cup, or bend with changes in humidity, quartersawn lumber shows very little movement over time and is the first choice for fine furniture and instrument makers.

A board is referred to as quartersawn when it is cut radially from the center of a log, and as the angle of the cut becomes less perpendicular to the face of the board, the classification of the board goes from quartersawn to Riftsawn. Riftsawn boards are basically a byproduct of the quartersawing process, and  fall somewhere in between plainsawn and quartersawn in terms of durability, cost ; sort of the lumber equivalent of mid-grade gasoline. Riftsawing process produces a more durable board than plainsawn the plainsawn method, and a more affordable alternative to pricey quartersawn lumber.

Rooftop Gardening

So want to have an organic garden, but, alas, your backyard is shadier than a politician. But you have noticed that the deck spends all day basking in glorious sunshine. Or perhaps you want a garden but have no backyard, placing responsibility for such an adventure squarely upon the roof. 

There’s a good chance that your deck is sturdy enough for the weight of garden beds, and it’s possible that even the roof is up to the task, but there are a series of essential factors to address that could very well mean the difference between pleasant mornings harvesting lettuce on the roof, and a fleet of emergency response vehicles, and perhaps a news reporter or two, racing to your home.

Simply put, you can’t just put what could add up to thousands of pounds of wood and soil above your living space, cross your fingers, and hope the roof doesn’t cave in.  Whether new construction, or reinforcing an existing building, a structure must be designed for the additional weight of a roof top garden, and any people using the garden. 

This equation involves not just the size and spacing of joist or rafters, but all the components of a building that are required to transfer that load down to the foundation, including: plywood roofing, rafter/joist sizes and span, girders, columns, walls and footings. 

For example, in order to evaluate a joist or girder, one needs to know the amount and type of load it supports, how far it spans and its size, type of material and its properties (allowable bending and shear stresses, etc).

It may not always be practical or cost effective to make changes to a structure in order to accommodate a roof top garden.  The main difficulty with a retrofit is the ability to determine if your home is actually strong enough to hold it up.  Most homeowners literally have to open up the walls and ceiling to find out.  If you live in a typical single family residence, chances are good your home’s roof  was not made to hold that much weight and you will need to add extra supports to accommodate a rooftop garden. Most decks, however, are capable of carrying the load of raised beds or other planters.

For a safe, rewarding rooftop gardening experience, follow these steps:

-determine that there is adequate sunlight and drainage on your roof or deck. Multifamily and commercial roofs and terraces will most likely have drains placed in low areas where water can be channeled into a gutter system
-determine how many people will be on the roof at one time, and how they will get up and down.
-address any HOA guidelines or concerns, and consider any other liabilities that could be an issue like your roof’s warranty, for example.
- Create a layout of the rooftop garden, including dimensions and volume of raised planters.
-Determine the weights and loads the rooftop garden design, as well as the estimated number of people would place on your building.
- Size or check the building members (beams, rafters, etc) from the roof down to the foundation

It’s always best to have a professional evaluate your structure to determine if it can safely bear the load of a garden, the basic science of it boils down to evaluating your roof or deck’s ability to support three weight categories :  dead, live or environmental loads.

Dead loads are weighted items that will be there all the time, including the materials in the actual roof or deck itself.  Typical rooftop garden  dead load types and their weights are:
        *Self weight of the structure - load varies
        *Conventional roof - 7 to 10 psf (pounds per square foot)
        *Small plants - 2 psf
        *Drainage layer - 2 to 3 psf
        *Soil density - 60 to 110 pcf (pounds per cubic foot) loads vary depending on soil mix

Live loads are dynamic or moveable loads associated with an areas usage -  In this case, mainly people.  Code dictates that different roof types be able to hold different amounts of weight.
        *In-accessible landscape roofs - 20 psf
        *Private or residential roofs - 40 psf
        *Multifamily or commercial roofs - 100 psf

Environmental loads such as snow, wind, seismic, rain, etc. Consider that your roof is most likely to fail during a rainfall when your garden’s grow medium is fully saturated.

Starting Seeds Indoors

While starting your own vegetable  plants from seed might not be as fulfilling as a life dedicated to fighting world hunger or forest fires,  it is pretty darn cool watching you’re your tiny seeds sprout grow into sturdy seedlings destined to yield produce for the kitchen table.

Starting Seeds Indoors

1.Start by filling a flat with grow medium  to within ¼” of the surface and level with a piece of wood.

2.Spread the selected seed variety evenly over the soil, and press down with the flat side of the piece of wood.

3. Cover the seeds to the depth specified on the packet – typically a depth of about 4 times their diameter - taking care to spread an even amount of soil over the seeds.

4.Again using the piece of wood, gently press down on the surface of the soil, and water it with a fine mist. The soil should be moist, but not soggy - like the consistency of a wrung out sponge.

5. Seal in moisture by covering the flat with a plastic dome or bag, and place it in front of a south facing window, or under florescent lights set to run 18 hours per day.  Because the flat is covered, you shouldn’t to need to water the soil until the first seedlings emerge and the dome or plastic bag is removed. Remove the plastic cover once the first seeds sprout.

Creating Ideal Conditions for Germination

-Place seedlings sear a sunny, south facing window, and/or under cool florescent lights set on a timer to run 18 hours per day. If plants are near a window, remember to rotate them regularly to ensure even growth. Seeds sprouted on a window without direct sun exposure will stretch and become spindly. If a south facing window isn’t convenient or unavailable, it’s best to invest in florescent lighting.

-Most seeds germinate best in a temperature range of 70-75 degrees, and sprouted seedlings prefer room temperatures of 60-70 degrees.

-Once the first sprouts have emerged, and the plastic cover has been removed, check the soil every day for lighter colored spots, which indicate that it is drying out. Gentle overhead watering with a fine mist is okay, but soaking the flat from the bottom carries less risk of damaging the tender young seedlings.

-The first set of leaves to emerge are called cotyledons which are actually food storage cells. As the seedlings continue to grow, the first set of true leaves will emerge. At this point, it’s time to fertilize the plants with an organic fish emulsion or seaweed based plant food.

-Seedlings can be thinned or transplanted when they have developed four true sets of leaves.

Special Seed Treatments

Some seeds require special handling to achieve good germination and growth.

-Scarification is a technique where the outer shell of the seed is scored with a knife, making it easier for the sprouted plant to emerge.

-Soaking seeds in warm water over  night improves germination. Remember to limit soaking to 48 hours as they may rot beyond that. Varieties that prefer soaking include corn, beans, okra, cucumber, melons, peas and squash.

-stratification involves changing the environment around the seeds to recreate natural weather cycles. Place seeds in a sealed plastic bag with about 4-5 times their volume in most peat moss or vermiculite, and place in the refrigerator for cold stratification or on a window sill for warm stratification. Once tiny white primary roots have emerged, the seeds are ready to be sown into sterile potting mix.

- Rhizobium  inoculant treatments added to bean seeds before planting will encourage a more vigorous plant capable of converting more atmospheric nitrogen into a usable form for the plant.

Bokashi Composting

Bokashi translates “fermented organic matter” in Japanese, and is a composting method that uses anaerobic bacteria in an airtight container to compost food scraps in indoor settings where traditional composting would be difficult - like a kitchen, apartment or garage.

While traditional composting relies on both aerobic and anaerobic bacteria to complete the decomposition process, the bokashi fermentation process happens in a closed system, which controls insects and smells. Unlike traditional composting, where the presence of dairy, bread and meat scraps would certainly attract rodents and create horrific odors, the bokashi process efficiently breaks down these items right alongside more familiar compost items like vegetable peelings and coffee grinds.

Billions of lacto-bacillus bacteria break down the scraps without the presence of oxygen, and because the system is sealed, no greenhouse gases are released, and no nutrients are leached away. This means that your garden’s soil will get the full benefit of the bacteria, sugars and nutrients in the finished compost, and because the anaerobic bacteria multiply so rapidly, the bokashi method happens much faster than traditional composting, creating a powerful amendment that’s ready to be integrated into your soil in around two weeks.

Sounds amazing right? It is, but remember that while the bokashi method has the unique ability to quickly break down meat and dairy as well as vegetable scraps in controlled settings ( sealed in an airtight plastic container),  for those who live on even a modest sized property, it would be all but impossible to compost the high volumes of leaves, grass clippings, old plants and other waste your yard produces using this method. Folks who own land will likely still need an outdoor compost station that is large enough to handle these plant based materials.

Tips for success using the bokashi method (courtesy of Bokashicomposting.com )

• The smaller the scraps that go into the composter the better.  Smaller scraps have more surface area and will break down faster relative to larger scraps.
• Use more bran for harder objects like bone, avocado skins, and corn cobs.
• Keep the composter out of the direct sun and away from direct heat sources.
• The optimum temperature for bokashi fermentation is 70-100 degrees Fahrenheit.
• Keep the lid closed tightly.  The process is anaerobic, so the less air exposure the better.
• Compress and compact food waste inside the bucket to remove air space.
• Cover the top layer of the waste inside the bucket with a plastic bag to help decrease air exposure.
• Conditions are not the exact same for everyone.  So feel free to experiment.  Let your nose and eyes be the guide.  White mold is good, green is bad.   A sweet pickled smell is good, a rancid odor is bad.  More bran, smaller waste piece, more surface contact, and warmer temperatures can help to correct these conditions.